This invention relates generally to the copying of a source document on reprographic devices to thereby generate a replication of the source document, and more particularly to embedding and/or altering data during the replication process, whereby the replicated document is substantially visually identical to the source document.
The phrase "reprographic devices" is intended to mean devices which provide for the convenient hardcopy reproduction or replication of documents, whether the documents are in paper, other hardcopy, or electronic form prior to the reproduction, including photocopiers, electronic printers, digital copiers, telecopiers, spirit duplicators, and the like, being used to reproduce all types of documents. Since the replication of the source document to the replicated document results in a substantially visually identical document, while the machine readable non-visual aspects are altered, the process according to the subject invention is directed to a quasi-reprographics technology.
The modification of "reprographics" by "quasi", intended to differentiate the technology of the present invention from that of a standard reprographic device, such as described above. In particular, in existing reprographic devices the object is to generate an image which represents a source image that has been copied. The present invention provides such a benefit but goes beyond this intention by embedding data in a manner where the copied image is visually unaltered to the human eye, however, information whichis not detectable by the human eye may be added or changed within the image. Thus the use of "quasi" is intended to assist in describing the unique aspect of the present invention.
Plain paper still is a favored recording medium for storing and transferring human readable information. The emergence of electronic document processing systems making it evident that the functional utility of plain paper and other types of hardcopy documents may be enhanced significantly when the human readable information they normally convey is supplemented by writing appropriate machine readable digital data on them. This machine readable data enables the hardcopy document to actively interact with such a document processing system in a variety of different ways when the document is scanned into the system by an ordinary input scanner. See, for example, commonly assigned U.S. Pat. No. 5,486,686 of Frank Zdybel, Jr. et al. on "Hardcopy Lossless Data Storage and Communications for Electronic Document Processing Systems", and U.S. Pat. No. 5,060,980 of Walter A. L. Johnson, et al., entitled "Form and System Utilizing Encoded Indications for Form Field Processing", which are hereby incorporated by reference.
As a general rule, digital data is recorded by writing two dimensional marks on a recording medium in accordance with a pattern which encodes the data. Among the different types of codes used to encode data, self-clocking glyph codes are known to be suitable for transferring digital values of various types (e.g., machine control instructions, data values, memory pointers, and executable binaries) back and forth synchronously between the electronic and hardcopy domains. They, therefore, are a promising interface technology for integrating hardcopy documents and computer controlled electronic document processing systems more or less seamlessly.
A self-clocking glyph code typically is generated by mapping logically ordered digital input values of a predetermined bit length into a predefined set of graphically unique symbols (i.e., "glyphs"), each of which is preassigned to the encoding of a different one of the permissible input values. Thus, each of the input values is transformed into and encoded by a corresponding glyph. These glyph encodings, in turn, are written on a hardcopy recording medium in accordance with a predetermined spatial formatting rule, thereby producing a glyph code that encodes the input values and preserves their logical ordering.
As will be appreciated, a code of the foregoing type carries the clock signal that is required for transferring the encoded digital values from the hardcopy domain to the electronic domain synchronously. Every input value is represented by a corresponding glyph, so the clock is embedded in the spatial distribution of the logically ordered glyphs. This is why these codes are referred to as "self-clocking" glyph codes. It also is to be understood that the self-clocking characteristic of these codes increases their tolerance to the degradation they may suffer while being replicated by copiers and/or facsimile systems. See commonly assigned Bloomberg et al. U.S. Pat. No. 5,168,147 on "Binary Image Processing for Decoding Self-Clocking Glyph Shape Codes" which hereby is incorporated by reference.
Another of the known advantages of these self-clocking glyph codes is that they can be composed of glyphs that are graphically distinguished from each other by machine detectable characteristics that are not easily perceived by the human eye. Thus, these codes can be used for recording machine readable digital information on hardcopy documents, without significantly degrading the aesthetic quality of those documents. For instance, the glyphs can be written using inks that are virtually invisible to the human eye under normal lighting conditions. Even more remarkably, glyphs written using visible inks, such as standard xerographic toners, can be of such small uniform size and written at a sufficiently high spatial density that the resulting glyph code has a generally uniform textured appearance to the human eye.
As pointed out in the aforementioned Bloomberg et al. patent (U.S. Pat. No. 5,168,147), digital values can be encoded in the rotation or profiles of such glyphs if the glyphs are rotationally variant or invariant, respectively. Also see Rob F. Tow, U.S. Pat. No. 5,315,098 on "Method and Means for Embedding Machine Readable Digital Data in Halftone Images", hereby incorporated by reference.
In addition to the aforementioned glyph codes, other codes such as serpentine codes can be embedded into documents such that they are imperceptible to the unaided human eye.
Zdybel, Jr. et al. U.S. Pat. No. 5,486,686, makes provision in electronic document processing systems for printing machine readable digital representations of electronic documents and human readable renderings of them on the same recording media using the same printing process. The integration of machine readable digital representations of electronic documents with the human readable hardcopy renderings of them being made not only to enhance the precision with which the structure and content of such electronic documents can be recovered by scanning such hardcopies into electronic document processing systems, but also as a mechanism for enabling recipients of scanned-in versions of such documents to identify and process annotations that were added to the hardcopies after they were printed and/or for alerting the recipients of the scanned-in documents to alterations that may have been made to the original human readable content of the hardcopy renderings.
Such a printing system typically includes sufficient capabilities to allow a user to create, edit and print human readable hardcopy renderings of electronic documents from the system. Therefore, Zdybel, Jr., U.S. Pat. No. 5,486,686, is directed to the creation and editing of documents as opposed to the reprographic arts, which takes a document existing in a fixed form and creates a replica thereof which is substantially visually identical to the original.
Daniele, U.S. Pat. No. 5,444,779, on "Electronic Copyright Royalty Accounting System for Using Glyphs", which is incorporated by reference, discloses a system for utilizing a printable, yet unobtrusive glyph or similar two-dimensionally encoded mark to identify copyrighted documents. Upon attempting to reproduce such a document, a glyph is detected, decoded and used to accurately collect and/or record a copyright royalty for the reproduction of the document or to prevent such reproduction. Furthermore, the glyph may also include additional information so as to enable an electronic copyright royalty accounting system, capable of interpreting the encoded information to track and/or account for copyright royalties which accrue during reproduction of all or portions of the original document.
It is noted that in a lens copier, the reprinting of the glyph in an original document would be accomplished during the normal reproduction of the document. When the original document is being reproduced from a digital image, assuming the glyph information was separable from the content portion of the document, the glyph portion could be printed anew in response to a re-coding of the decoded glyph information. Further, it is suggested new information could also be added in this manner.
While Daniele, U.S. Pat. No. 5,444,779, does discuss the reprographic generation of a document having human readable data as well as electronic readable data in the same document, Daniele only suggests such reproduction to a document which has glyph data previously embedded. Also, as to the suggestion in Daniele of adding additional glyph information to the document, such an addition would increase the glyph encoded area thereby perceptively altering the reproduced document. Further, this patent teaches that the two-dimensional code, such as the glyph code, is to be located in a predetermined position on the document sheet, particularly side or bottom margins are suggested. However, under this teaching when, innocently or with intent, the border areas are not copied, the reproduced document will not hold any embedded machine readable data.
Consequently, it will be evident that it would be a significant improvement in the reproduction of documents if it were possible to quasi-reprographically replicate a source document configured with either no embedded data or selected areas of embedded data such that embedded data is added or existing embedded data is altered while the replicated document is visually substantially identical to the source document. It would further be beneficial to quasi-reprographically replicate a source document containing embedded data, where the embedded data is replaced by newly generated data, and the data is added such that a predefined embedded data area is substantially identical to the human eye, and where during the quasi-reprographic process, selection of appropriate areas for the embedding of data are determined.